Home » Ask & Discuss » Mathematics. » Algebra « Back to Discussion

Algebra

New kid on the Block

Joined:	24 Jan 2007
Post:	18

22 Feb 2007 19:25:29 IST

0 People liked this

418

progression---easiest problem

None

A gardner wants to water 50 trees. The first tree is 10 m away from where a well is where he has to fill the water from. There is a gap of 5 m between each tree.
How much distance does he have to cover?
Please anybody explain the solution and remember i don't have the answer with me.
Thank you

Share this article on:

Comments (2)

Asmita Bhattacharya

Blazing goIITian

Joined: 18 Dec 2006

Posts: 305

22 Feb 2007 19:33:58 IST

Like 0 people liked this

Here the dis. covered 4 watering the 1st plant & returning back=10m+10m=20m

For the 2nd plant it's 15m+15m=30m

For the 3rd one it's 40m ...........

So total distance=50/2{2*20+49*10}

=13250m

Now we 've 2 subtract the dis. between the 50th plant & the well 2 get the correct ans. which is equal to 10+49*5=255m

So the required ans. is 13250-255=12995m

Bipin Dubey

Forum Expert

Joined: 23 Jan 2007

Posts: 7942

23 Feb 2007 17:26:44 IST

Like 1 people liked this

Its a simple AP problem.
For the 1st tree distance travelled is (10+10) = 20 m
For 2nd tree = (15+15) = 30 m
For 3rd tree = 40 m ....................and so on

For the 50th tree he only travels from well to tree and not back to well.
Hence for 50th tree distance travelled = 10 + 49*5 = 255 m

Hence distance travelled upto 49th tree = sum of AP
= (49/2)(2*20 + (49-1)*10)
= 12740 m

Hence total distance travelled = 12740 + 255 = 12995 m

Best Wishes

Quick Reply

Reply

	Some HTML allowed.
	Keep your comments above the belt or risk having them deleted.
	Signup for a avatar to have your pictures show up by your comment
	If Members see a thread that violates the Posting Rules, bring it to the attention of the Moderator Team